So l am doing something right then. I regularly turn off MCBs before turning off the main switch. It's a practice ive followed because of something my tutor told me regarding sparks appearing at the main switch, if you don't.
However due to nerves on my Level 3, l was so paranoid about doing safe isolation (failure to do this was instant ejection from exam for safety reasons) that l flicked off the main switch, then the isolater, then locked off, then the MCBs. Yeah l know the totally wrong order.
Does the same apply to then RCDs Teletrix? Should they be opened as well before opening Main Switch?